A county oversight has allowed three years of assessments to go uncollected until now. And with other changes, users are extra miffed.

Thanks to a bureaucratic oversight, the county essentially forgot to collect taxes on boat slips and dry storage in the marina for the last three years. Now, the county assessor will be sending out as many as 6,000 notices in the next week informing boaters of their obligation to pay the current and back-due taxes.

The precise amount won't be known until the treasurer's office issues the tax bills, but by some rough estimates the total could be more than $1 million. Individual assessments range from $70 to $250 per year, depending on the size of the slip.

What has made boaters see red is that the tariff -- known as possessory interest tax -- was once included in the monthly slip payments they made to management companies that operated the marina.

But after the county took control of the lease agreements in 2001, it no longer applied that portion of their payments to the tax. So some boaters feel they are now being forced to pay the tax twice.

How the county could have overlooked the tax component of the slip payments -- and not noticed its own dip in tax revenue for three years running -- has puzzled and incensed boaters, turning a bastion of middle- and upper-class leisure lovers into feisty government critics.

Ron Brown, who has docked his 38-foot boat at the marina for 21 years, said he is thinking of selling the vessel and moving out after the summer boating season.

"I don't see how they get away with it," said Brown, a 69-year-old San Clemente resident, as he came in off the dock of the Chili Pepper. "They can do anything they want. If you don't pay it, what're you going to do?"

Judging from a survey of the marina on a recent crystalline day, as gleaming white boats with names such as Nauti Boy bobbed in the cobalt water, it's hard to imagine anyone will be sunk by a few hundred dollars in additional taxes.

But the bills are arriving amid rising frustration over a county plan to boost development in the marina -- which has already led to year-over-year slip fee hikes to pay for the work -- while also slashing the number of slips for the smallest boats in favor of mega-yacht spots. Many locals see the plans as effectively gentrifying what had been one of the few harbors in Southern California affordable for middle-class boaters.

"It's becoming very expensive," said Bruce Heyman, the president of the Dana Point Boaters Assn. "For some members, it's pricing them out of the water, it's pricing them out of the slips. Clearly, our view is that that's not what we should be doing here. We should be resisting that urge."

Webster Guillory, the county assessor, said the slip assessments just fell through the cracks. When the county took over the leases, the new contracts stated that boaters would now be responsible for paying their own possessory interest taxes. But county officials in charge of the marina neglected to mention that to the assessor's office until two years later.

During that time, he didn't even know he was supposed to be assessing the slips, he said, and that he undertook the work as soon as he was made aware of it in November.

"In this case, I did not get timely information, so now that I have it I'm just responding to it," Guillory said. He added there was no way the county treasurer's office could have known the taxes were going unpaid in previous years, because he hadn't issued the assessments for them.

Now, the marina's roughly 3,000 boaters are about to receive as many as three assessments apiece, one for each year they held the slip and the tax went unpaid. Tax bills will be issued by the treasurer's office about a month after the assessments go out.

Heyman, the boating association leader, said they have 60 days to appeal the bills and hope they can negotiate some sort of compromise with the county. If not, they may consider other options.

To others, the nuances of what kind of tax, or who was responsible for it, are lost in the face of simple frustration at the rising fees.

"It just annoys me that when the county is the landlord, you have rent, and then a tax on the rent," said Phil Wolcott of Dana Point, who was relaxing in the sun on the deck of his boat, the Wind-E-Scape. "I don't think the county needs any other little taxes for us."